Re: [UrbanSim-Users] travel_data

Hi,

Can someone please help me figure out how to alter the code to use
travel times instead of logsums? Exactly which files need to be
altered, and how should they be altered?

Thanks,
Jen

Paul Waddell wrote:
> UrbanSim is generally connected to an existing regional travel model,
> from which either composite utilities from the mode choice model (aka
> logsums) or more generally, congested travel times by mode for the
> home-based-work purpose in the a.m. peak period (or other similar
> measures) are extracted for each travel model year. The connections can
> be automated - we have done this with emme/2 and transcad most recently,
> and previously with TP+ and Minutp. It essentially requires an
> interface to be written for whichever travel model you are using, to
> summarize UrbanSim output and generate the inputs required for the
> travel model; and in the other direction, to extract travel model
> outputs and generate the travel_data table -- with whatever travel
> measures you want to use. Logsums are by no means required, and we have
> found them to be somewhat unstable in practice (though they look good in
> theory) - with small changes in the travel model causing large shifts in
> the logsum measures and therefore precipitating a recalibration of UrbanSim.
>
>
Received on Mon Aug 13 2007 - 12:34:04 PDT